Magnetic layer

ABSTRACT

An apparatus includes a substrate and a magnetic layer coupled to the substrate. The magnetic layer includes an alloy that has magnetic hardness that is a function of the degree of chemical ordering of the alloy. The degree of chemical ordering of the alloy in a first portion of the magnetic layer is greater than the degree of chemical ordering of the alloy in a second portion of the magnetic layer, and the first portion of the magnetic layer is closer to the substrate than the second portion of the magnetic layer.

BACKGROUND

The present application relates generally to magnetic layers.

In one instance, magnetic layers may be present in recording media.Recording media can be utilized in a variety of applications, including,but not limited to, computers and communication applications. Data maybe stored in digital format via electromagnetic encoding on a magnetizedmedium, where different patterns of magnetization may be read and/orwritten by a read-and-write head. To write, the head interacts with themagnetized medium by converting a magnetic field of a ferromagneticgrain of the medium to electric current or vice versa. To read, the headsenses patterns of individual fields in the magnetized medium. Theamount of data recordable upon a particular media arrangement is afunction of the orientation of the grains in the magnetized media, suchas being perpendicularly or horizontally arranged with respect to arecording surface. Perpendicular arrangement generally allows for a morecompact medium, however the thermal stability of such a medium may bedecreased.

SUMMARY

One embodiment relates to an apparatus that includes a substrate and amagnetic layer coupled to the substrate. The magnetic layer includes analloy that has magnetic hardness that is a function of the degree ofchemical ordering of the alloy. The degree of chemical ordering of thealloy in a first portion of the magnetic layer is greater than thedegree of chemical ordering of the alloy in a second portion of themagnetic layer. The first portion of the magnetic layer is closer to thesubstrate than the second portion of the magnetic layer.

Another embodiment relates to a system, which includes a recordingsurface. The recording surface includes a magnetic layer that is atleast partially configurable via a magnetic head. The magnetic layerincludes an alloy that has a magnetic hardness that is a function of themolecular structure of the alloy. Further, the magnetic layer includesdiscrete sub-layers such that, within each sub-layer, the alloy has aconsistent molecular structure, and between the sub-layers the molecularstructure of the alloy varies.

Yet another embodiment relates to a process of manufacturing, whichincludes providing a substrate and an alloy. The alloy includes iron andplatinum. The process further includes coupling a layer of the alloy andthe substrate, and changing the temperature of the alloy to vary thedegree of chemical ordering of the alloy with respect to distance fromthe substrate within the layer.

Alternative embodiments relate to other features and combinations offeatures as may be generally recited in the claims.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a schematic illustration of a disk driveaccording to an embodiment.

FIG. 2 is a sectional view of a schematic illustration of recordingmedia according to an embodiment.

FIG. 3 is a sectional view of a schematic illustration of recordingmedia according to another embodiment.

FIG. 4 is a sectional view of a schematic illustration of recordingmedia according to yet another embodiment.

FIG. 5 is a top view of a schematic illustration of the section of therecording media of FIG. 4 taken along line 5-5 of FIG. 4 according tostill another embodiment.

FIG. 6 is a graphical representation of temperature as a function oftime for processes of manufacturing recording media according toembodiments.

FIG. 7 is a sectional view of recording media according to anotherembodiment.

FIG. 8 is a graphical representation of temperature as a function oftime for processes of manufacturing recording media according to otherembodiments.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the embodiments indetail, it should be understood that the present application is notlimited to the details or methodology set forth in the description orillustrated in the figures. It should also be understood that theterminology is for the purpose of description only and should not beregarded as limiting.

Referring to FIG. 1, a disk drive, such as a hard disk drive 110,includes a housing 112 supporting a recording media, such as a disk 114having a recording surface 116 (e.g., platter, flat circular disk), anda head 118 (e.g., read-and-write head). In some embodiments, such as indisk drive 110, the recording surface 116 rotates about a spindle 120,and the head 118 is moved over the recording surface 116 by an arm 122(e.g., actuator arm, access arm) that is rotated about a pivot 124 by anactuator 126, such as a voice coil actuator or a stepper motor. Althoughshown in FIG. 1 as disk 114 in hard drive 110, the recording media canbe embodied as other types of media or have a variety of shapes orgeometries. Further, the recording media can be utilized in a variety ofstorage devices.

According to an embodiment, the recording surface 116 includes amagnetic layer (see, e.g., magnetic layer 214 as shown in FIG. 2), whichhas ferromagnetic grains. Each ferromagnetic grain has a magneticdipole, and the localized magnetic field of the dipole is configured toprovide binary information. As the head 118 passes over a grain on therecording surface 116, components of the head 118 (e.g.,magneto-resistive read element, thin-film write element) are configuredto detect the magnetic field of the grain and/or modify the field. Insome embodiments the grains are generally arranged perpendicularly withrespect to the recording surface 116.

According to other embodiments, a wide range of other non-removable orremovable disk drives may include recording surfaces accessed via one ormore fixed or moving heads. A head may not be included. The grains, insome contemplated embodiments, are arranged horizontally or areotherwise angled with respect to a recording surface. A recordingsurface may include more than one magnetic layer, and the recordingsurface may be cylindrical, spherical, rectangular, or otherwise shapedin some alternate embodiments.

Referring to FIG. 2, a recording media 210 includes a substrate 212 anda magnetic layer 214. The substrate 212 may be in the form of a disk ofa disk drive (see, e.g., disk 114 and hard disk drive 110 as shown inFIG. 1), and may be at least partially formed from glass, aluminumalloy, composite, or another non-magnetic material. In some embodimentsa seed layer 216 may be provided between the substrate 212 and themagnetic layer 214 to facilitate thin film development. In some suchembodiments, the seed layer 216 includes magnesium oxide (MgO),ruthenium aluminum alloy (RuAl), copper (Cu), chromium (Cr), molybdenum(Mo), tungsten (W), and/or other materials. In contemplated embodiments,seed- and/or under-layers consist of several layers, including a softunder-layer (SUL). Also, in some embodiments an overcoat 218 of carbon(C) or another material and/or lubricant may be provided over themagnetic layer 214 for protection and/or support thereof.

According to an embodiment, the magnetic layer 214 is formed from asingle alloy that has a magnetic hardness (denoted by “H_(K)”) that is afunction of the degree of chemical ordering of the alloy. In some suchembodiments, the magnetic hardness of the alloy selected to form themagnetic layer 214 is directly proportional to the degree of chemicalordering of the alloy, where a fully-ordered form of the alloy has asignificantly greater H_(K) than a fully-disordered form of the alloy.Alternatively, in some embodiments the magnetic layer 214 is formed froma single alloy that has an H_(K) that is a function of the molecularstructure of the alloy. The alloy, having a first molecular structure(e.g., ordered L1₀), has a greater H_(K) than the alloy having a secondmolecular structure (e.g., disordered, face-centered cubic (fcc) phase).

Use of a single alloy for the magnetic layer 214 may simplifymanufacturing of the magnetic layer 214 by removing parts of themanufacturing process, such as adding a second material, mixingmaterials, preconditioning multiple materials, and the like. In anembodiment, an alloy including iron (Fe) and platinum (Pt) is used withthe magnetic layer 214 because of the relatively large H_(K)differential between different phases associated with such alloys. Inalternative contemplated embodiments, other alloys may include Fe andPd, cobalt (Co) and Pt, nickel (Ni) and Fe, manganese (Mn) and aluminum(Al), titanium (Ti) and Al, other Co-alloys, or other materials.

According to an embodiment, the alloy in a first portion 220 (e.g.,sectional plane, sub-layer, region) of the magnetic layer 214 has agreater degree of chemical ordering that the alloy in a second portion222 of the magnetic layer 214. In some embodiments, the first portion220 of the magnetic layer 214 extends over the second portion 222, andis in direct contact therewith. While in order embodiments the firstportion 220 is separated from the second portion 222 by one or moreintermediate portions of the magnetic layer 214. The two portions 220,222 may be magnetized in opposite orientations to form anexchanged-coupled composite, with the first portion 220 magneticallyreinforcing the second portion 222 so as to provide reduced fieldstrength and increased thermal stability characteristics of therecording media 210.

According to an embodiment, the first portion 220 of the magnetic layer214 is closer to the substrate 212 than the second portion 222, suchthat the magnetic layer 214 is magnetically harder closer to thesubstrate 212 than further from the substrate 212. In at least oneembodiment, the alloy of the first portion 220 of the magnetic layer 214is primarily composed of a fully-ordered form of the alloy. In othercontemplated embodiments, the magnetic layer 214 is arranged with amagnetically-harder portion of the magnetic layer 214 further from thesubstrate 212 than a magnetically-softer portion of the magnetic layer214.

Still referring to FIG. 2, the magnetic layer 214 includes discretesub-layers 224, 226 such that, within each sub-layer 224, 226, the alloyhas a consistent molecular structure, but between the sub-layers 224,226 the molecular structure of the alloy varies. Alternatively, in someembodiments the degree of chemical ordering of the alloy in the magneticlayer 214 varies discretely with respect to distance from the substrate212 such that the alloy, in the first sub-layer 224, which is closer tothe substrate 212, has a greater degree of chemical ordering than doesthe alloy in the second sub-layer 226, which is further from thesubstrate 212. In some embodiments, the alloy in the first sub-layer 224is fully ordered, while the alloy in the second sub-layer 226 isdisordered (e.g., fully disordered). Although shown in FIG. 2 to haveabout the same thickness, in other embodiments the first sub-layer isthicker than the second sub-layer, or vice versa.

According to an embodiment, the first and second sub-layers 224, 226have substantially uniform thicknesses H₁, H₂. In some embodiments, thethicknesses H₁, H₂ of the first and second sub-layers 224, 226 are eachbetween about one to ten nanometers. In other embodiments, one or bothof the thicknesses H₁, H₂ of the first and second sub-layers 224, 226are less than fifty nanometers, such as less than about thirtynanometers. In still other contemplated embodiments, one or both of thethicknesses H₁, H₂ of the first and second sub-layers 224, 226 are lessthan a nanometer or more than fifty nanometers. According to anembodiment, the combined thickness H_(T) of the first and secondsub-layers 224, 226 is between one-hundred picometers and one-hundrednanometers, such as between about five and thirty nanometers.

Referring to FIG. 3, a recording media 310 includes a substrate 312 anda magnetic layer 314. The magnetic layer 314 includes first, second, andthird sub-layers 316, 318, 320. According to an embodiment, at least twoof the sub-layers 316, 318, 320 are formed from a single alloy that hasan H_(K) that is a function of the degree of chemical ordering of thealloy. In some embodiments, the first sub-layer 316 includes afully-ordered form of the alloy having a relatively high H_(K) (e.g.,magnetically hard) and the second sub-layer 318 includes a fullydisordered form of the alloy having a relatively low H_(K) (e.g.,magnetically soft).

In some such embodiments, the third sub-layer 320 includes the alloyhaving a degree of chemical ordering that is between the degree ofchemical ordering of the alloy in the first and second sub-layers 316,318. The molecular structure of the alloy in the third sub-layer 320 isconsistent in that the degree of chemical ordering of the thirdsub-layer 320 is uniform throughout the third sub-layer 320. Use of athird sub-layer 320 having a degree of chemical ordering intermediate tothe first and second sub-layers 316, 318 is intended to further reducethe switching field while maintaining thermal stability of the recordingmedia 310. In other such embodiments, the third sub-layer 320 includes amaterial that is not the alloy, such as a non-magnetic material or adifferent magnetic material. In other contemplated embodiments, amagnetic layer includes more than three discrete sub-layers.

Referring now to FIGS. 4-5, a recording media 410 includes a magneticlayer 412 formed from a single alloy arranged in a first sub-layer 414and a second sub-layer 416. By way of non-limiting example, therecording media 410 may be used with the disk drive 110, where FIG. 4 isa section of the disk 114 that is perpendicular to the recording surface116, and FIG. 5 is a section of the disk 114 that is parallel to therecording surface 116 and within the disk 114. In such an example, thetop of FIG. 4 corresponds to the visible portion of the recordingsurface 116 in FIG. 4. According to an embodiment, the alloy includes Feand Pt, and is herein referred to as “FePt—X,” where the “X” of FePt—Xdesignates the possible addition of one or more of a variety of elementsor compounds, such as at least one of chromium (Cr), Ni, Cu, silver(Ag), C, boron (B), boron nitride (BN), silicon dioxide (SiO₂),titantium dioxide (TiO₂), and boron trioxide (B₂O₃). While an element orcompound in addition to Fe and Pt in FePt—X may be used with recordingmedia, in contemplated embodiments FePt—X may not include any elementsor compounds in addition to Fe and Pt.

When arranged in a face-centered tetragonal molecular structure (“fctphase”; e.g., fully-ordered phase, L1₀ phase), FePt—X is believed by theApplicants to be one of the magnetically hardest materials. However whenarranged in a face-centered cubic molecular structure (“fcc phase”;e.g., fully-disordered phase), FePt—X is believed to be magneticallysoft. Use of FePt—X for the alloy of the magnetic layer 412 may be used,because the disparity between the H_(K)-values associated with the fctand fcc phases of FePt—X provides a particularly efficientexchange-coupled composite structure between the first and secondsub-layers 414, 416 of the magnetic layer 412 of the recording media410. For FePt, Applicants believe the anisotropy field H_(K) could rangefrom 0 for a fully disordered fcc phase up to 14 Tesla (or 140 kOe) forthe completely ordered L1₀ phase. However, in other contemplatedembodiments, other alloys or materials may be used.

According to an embodiment, the first sub-layer 414 of the magneticlayer 412 includes the FePt—X alloy having a granular microstructure.During manufacturing of the magnetic layer 412, columnar grain growth ofthe FePt—X alloy in the fct phase is controlled to provide grains 418having an average grain size (e.g., diameter, or longest distancebetween two points on the surface) of less than about ten nanometers(see FIG. 5), such as less than twenty nanometers. According to anembodiment, C is used as a boundary material 420 for the alloy, becauseC is believed to facilitate formation of the granular microstructure ofthe first sub-layer 414 during manufacturing of the magnetic layer 412.

Referring generally to FIGS. 6 and 8, an alloy is selected for use in amagnetic layer of recording media (see, e.g., magnetic layer 214 andrecording media 210 as shown in FIG. 2) that has an H_(K) that iscontrollable during manufacturing of the magnetic layer as a function ofone or more conditions (e.g., parameters, variables) that affect themolecular structure or degree of chemical ordering of the alloy. Somesuch conditions may include temperature of the alloy, additivematerials, duration of time undergoing such conditions during a processof manufacturing the magnetic layer, etc. The alloy may be made toundergo the conditions during deposition of the magnetic layer on asubstrate (e.g., via thin film deposition, physical deposition, chemicaldeposition, sputtering) or after the magnetic layer has been deposited(e.g., post-deposition treatment, annealing).

According to an embodiment, the molecular structure or degree ofchemical ordering of the alloy is monotonically controllable as afunction of one parameter, such as temperature. In such an embodiment,variation of the temperature of the alloy, either during deposition orafter deposition, may be used to affect the molecular structure ordegree of chemical ordering of the alloy. Applicants believe that thedegree of chemical ordering of the FePt—X alloy, described above, ismonotonically controllable as a function of process temperature. Noadditives are required to change the molecular structure of the FePt—Xalloy from the fct phase to the fcc phase or vice versa. Use of an alloythat is monotonically controllable is intended to simplify themanufacturing process by obviating accounting for coupling effectsbetween two or more variables, operating separate components configuredto control different parameters, etc.

Referring specifically to FIG. 6, the process temperature of an alloymay be changed as the alloy is deposited to form a magnetic layer ofrecording media (see, e.g., magnetic layer 214 and recording media 210as shown in FIG. 2), from a first temperature facilitating ordering ofthe alloy to a second temperature facilitating a less-orderedarrangement or a fully disordered arrangement of the alloy. As shown ina graphical representation 510 of FIG. 6, three hypotheticalmanufacturing processes 512, 514, 516 lower the temperature of the alloyas the alloy is being deposited on a substrate. During eachmanufacturing process 512, 514, 516, the rate of deposition of the alloymay be constant or may vary to facilitate particular responses in theformation of the magnetic layer, such as columnar growth of the alloy.

The first process 512 provides a single drop in temperature (e.g.,discontinuity, sharp change in temperature), from a first temperature(e.g., about 700-degree Celsius for FePt—X alloy) believed to facilitatea fully-ordered form of the alloy to a second temperature (e.g., roomtemperature, 30-degree Celsius, greater than 500-degrees below than thefirst temperature) believed to facilitate a disordered form of thealloy. The first process 512 is intended to provide two sub-layers ofthe magnetic layer (see, e.g., magnetic layer 214 and recording media210 as shown in FIG. 2), where the first sub-layer is magnetically hardand the second sub-layer is magnetically soft.

The second and third processes 514, 516 shown in FIG. 6 include processtemperature-versus-time curves intended to provide more than twosub-layers within a magnetic layer of recording media by incrementallyreducing the process temperature to one or more temperatures associatedwith intermediate degrees of chemical ordering of the alloy. In othercontemplated embodiments, the temperature may be discretely raised, orboth discretely raised and lowered, to provide a pre-determinedstructure of the magnetic layer.

In other contemplated embodiments, a first sub-layer of the magneticlayer may be deposited on the substrate, followed by annealing of thefirst sub-layer. The first sub-layer may then be cooled in a mannerdesigned to facilitate or inhibit a particular molecular structure(e.g., crystallization) of the alloy. Then a second sub-layer of themagnetic layer may be deposited over the first sub-layer, andsubsequently annealed and cooled. The annealing corresponding to thefirst and second sub-layers may be different, with each particularlytailored to produce a ratio of molecules having first and secondmolecular structures in the alloy. Additional sub-layers (e.g., third,fourth, fifth) may be added such that a graduated transition withrespect to distance from the substrate is provided in the magneticlayer, such as from predominance of the first molecular structure topredominance of the second molecular structure.

Referring now to FIG. 7, a recording media 610 includes a substrate 612and a magnetic layer 614 coupled to the substrate 612. The magneticlayer 614 includes a single alloy that has an H_(K) that is a functionof the degree of chemical ordering of the alloy. The degree of chemicalordering of the alloy in a first portion 616 of the magnetic layer 614is greater than the degree of chemical ordering in a second portion 618of the magnetic layer 614. In some embodiments, the first portion 616 ofthe magnetic layer 614 is closer to the substrate 612 than the secondportion 618 of the magnetic layer 614, while in other embodiments, viceversa.

Still referring to FIG. 7, the degree of chemical ordering of the alloycontinuously changes within the magnetic layer 614. According to anembodiment, the degree of chemical ordering continuously decreases withrespect to distance from the substrate 612 within the magnetic layer614. In one such embodiment, the degree of chemical order continuouslydecreases within the magnetic layer 614 at a constant rate, from afully-ordered portion of the magnetic layer to a fully disorderedportion of the magnetic layer 614.

Referring now to FIG. 8, a graphical representation 710 of processtemperature-versus-time curves are shown for four hypotheticalmanufacturing processes 712, 714, 716, 718 intended to respectivelyprovide magnetic layers where the chemical ordering of a single alloywithin each magnetic layer continuously changes (e.g., decreases) withrespect to distance from a substrate. In a first process 712, thetemperature is continuously decreased at a constant rate, which isintended to provide a magnetic layer that continuously transitions froma first degree of chemical ordering (e.g., fully ordered) to a seconddegree of chemical ordering (e.g., fully disordered), at a constant rateof change in the chemical ordering. The second process 714 is intendedto provide a greater proportion of the magnetic layer having a higherdegree of chemical ordering than the third process 716. The fourthprocess 718 is intended to form sub-layers of the alloy having aparticular degree of chemical ordering, where the sub-layerscontinuously transition into one another. In other contemplatedembodiments, the temperature may be continuously raised, or bothcontinuously raised and lowered, to provide a predetermined structure ofthe magnetic layer. In still other contemplated embodiments, a processtemperature may include continuously variable temperature changes,segments of constant temperatures, and/or discontinuous temperaturechanges (see, e.g., FIG. 6).

In other contemplated embodiments, annealing of a magnetic layer isintended to provide a continuous transition within the magnetic layer ofa single alloy in a first phase to the alloy in a second phase. In somesuch embodiments, the magnetic layer may be first be deposited on asubstrate (e.g., recording surface of a disk) in a fully-ordered phase.Annealing and cooling may be conducted such that the alloy on one side(e.g., exposed side) of the magnetic layer is changed to a disorderedphase while the alloy on another side of the magnetic layer remains inthe fully-ordered phase. In such a process, the temperature may becontrolled to provide a predetermined transition rate between the twophases of the alloy within the magnetic layer.

The construction and arrangements of the recording media, as shown inthe various embodiments, are illustrative only. Although only a fewembodiments have been described in detail in this disclosure, manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Someelements shown as integrally formed may be constructed of multiple partsor elements, the position of elements may be reversed or otherwisevaried, and the nature or number of discrete elements or positions maybe altered or varied. The order or sequence of any process, logicalalgorithm, or method steps may be varied or re-sequenced according toalternative embodiments. For example, while FIGS. 6 and 8 show processtemperature as a function of time, in other manufacturing processes ofrecording media, as described above, other parameters or multipleparameters may be changed with respect to time or another independentvariable to provide a predetermined structure for a magnetic layer.Other substitutions, modifications, changes and omissions may also bemade in the design, operating conditions and arrangement of the variousembodiments without departing from the scope of the present invention.

What is claimed is:
 1. A process, comprising: coupling a magnetic layerof an iron platinum alloy and a substrate; and changing the temperatureof the alloy as the alloy is deposited on the substrate to vary thedegree of chemical ordering of the alloy with respect to distance fromthe substrate within the layer, wherein the degree of chemical orderingof the alloy decreases within the magnetic layer with respect todistance from the substrate.
 2. The process of claim 1, wherein changingthe temperature further comprises changing the temperature of the alloyby over 500-degrees Celsius as the alloy is deposited on the substrate.3. The process of claim 1, wherein changing the temperature furthercomprises continuously changing the temperature of the alloy as thealloy is deposited on the substrate.
 4. The process of claim 1, whereinthe alloy in a first portion of the magnetic layer consists essentiallyof a fully-ordered form of the alloy.
 5. The process of claim 1, whereinthe alloy in a first portion of the magnetic layer has a granularmicrostructure with an average grain size of less than about tennanometers.
 6. The process of claim 5, further comprising using carbonas a boundary material for the alloy in the first portion of themagnetic layer.
 7. The process of claim 6, wherein the alloy furthercomprises at least one of copper, chromium, zirconium, boron, tantalum,silicon dioxide, magnesium oxide, aluminum oxide, and boron trioxide. 8.The process of claim 1, further comprising: depositing a seed layerbetween the substrate and the magnetic layer; and depositing an overcoatoverlaying the magnetic layer, wherein the compositions of the seedlayer and the overcoat do not include iron and platinum.
 9. A process,comprising: changing the temperature of an iron platinum alloy as thealloy is deposited on a substrate to vary the degree of chemicalordering of the alloy with respect to distance from the substrate bydiscretely varying the degree such that the alloy, in a first sub-layercloser to the substrate, has a greater degree of chemical ordering thandoes the alloy in a second sub-layer that is further from the substrate.10. The process of claim 9, wherein changing the temperature furthercomprises changing the temperature of the alloy by annealing.
 11. Theprocess of claim 9, wherein the alloy in the first sub-layer is fullyordered, and wherein the alloy in the second sub-layer is disordered.12. The process of claim 9, wherein the alloy in the first sub-layerconsists essentially of molecules having a face-centered tetragonalmolecular structure, and wherein the alloy in the second sub-layerconsists essentially of molecules having a face-centered cubic molecularstructure.
 13. The process of claim 12, wherein the first sub-layer hasa substantially uniform thickness, and wherein the second sub-layer hasa substantially uniform thickness.
 14. The process of claim 13, whereinthe thickness of the first sub-layer is between about one to tennanometers, and wherein the thickness of the second sub-layer is betweenabout one to ten nanometers.
 15. The process of claim 13, wherein thecombined thickness of the first and second sub-layers is between aboutfive to thirty nanometers.
 16. A process, comprising: decreasing thetemperature of an iron platinum alloy as the alloy is deposited on asubstrate to vary the degree of chemical ordering of the alloy withrespect to distance from the substrate, wherein decreasing thetemperature comprises decreasing the temperature of the alloy by over500-degrees Celsius.
 17. The process of claim 16, wherein the alloy isdeposited at a first temperature of about 700-degrees Celsius andsubsequently deposited at a second temperature of about 200-degrees orless.
 18. The process of claim 17, wherein the second temperature isroom temperature.